원문정보
초록
영어
In a previous study, we co-cultured the novel strain Bacillus licheniformis SGP1 with Clostridium tyrobutyricum ATCC 25755 for butyric acid production using sucrose as a carbon source in RCM medium. In this co-culture, B. licheniformis produces levansucrase enzyme in the medium which degrades sucrose into monosaccharides allowing C. tyrobutyricum to utilize them along with the lactic acid produced by B. licheniformis for butyric acid production. In this study, we wanted to determine the effect of different factors on the growth of this novel Bacillus strain and its levansucrase production and activity. Optimum pH was around 7.0. Optimum temperature for growth is 37⁰C. Enzyme production is decreased dramatically as the temperature rises from 30⁰C to 43⁰C and the reverse happens for enzyme activity. This enzyme has a molecular weight of 55 KDa. In fed-batch fermentation at pH 5.50 and temperature of 37⁰C, the co-culture could give a final butyrate concentration of 36 g/L with productivity equals 0.24 g/L/hr, while at 40⁰C, we could get 28.6 g/L and 0.34 g/L/hr respectively. Real time PCR experiment was done finally to determine the growth pattern of the two strains in the co-culture.